Hermetic compressor

ABSTRACT

This hermetic compressor includes a regulation mechanism, which is arranged between a lower washer and an upper end face of a bearing, for regulating a movable distance in a thrust direction of the lower washer so that the movable distance can be shorter than clearance between an inner diameter of the lower washer and an outer diameter of a main shaft portion. It is possible to prevent the inner diameter of the lower washer from coming into contact with the outer diameter of the main shaft portion by this regulation mechanism.

TECHNICAL FIELD

The present invention relates to a hermetic compressor mainly used for arefrigerator for domestic use.

BACKGROUND ART

In a conventional hermetic compressor in which a thrust ball bearing isemployed for enhancing the efficiency, washers arranged on the upper andlower sides of the thrust ball bearing can be freely rotated round theshaft and the bearing. This prior art is disclosed, for example, in theofficial gazette of Japanese Patent Unexamined Publication No. 61-53474.

Referring to the drawings, the above conventional hermetic compressorwill be explained below.

FIG. 18 is a longitudinal sectional view of the conventional hermeticcompressor and FIG. 19 is an enlarged sectional view showing a primaryportion of the conventional hermetic compressor.

In FIGS. 18 and 19, refrigerant 3002 is charged into hermetic container3001. Further, refrigerating machine oil 3003 is stored in hermeticcontainer 3001.

Electrically driving element 3011 includes: stator 3012 connected to anexternal electric power source (not shown): and rotor 3013 arrangedinside stator 3012, forming a predetermined gap between rotor 3013 andstator 3012.

Compression element 3021 includes: shaft 3022; cylinder block 3023;bearing 3024; piston 3025 reciprocating in compression chamber 3023 a;connecting portion 3026; and thrust ball bearing 3031. Shaft 3022includes: main shaft portion 3022 a; and eccentric shaft portion 3022 c.Cylinder block 3023 is fixed under stator 3012 and forms compressionchamber 3023 a. Bearing 3024 supports shaft 3022 provided in cylinderblock 3023. Piston 3025 is reciprocated in compression chamber 3023 a.Connecting portion 3026 connects piston 3025 with eccentric shaftportion 3022 c. Thrust ball bearing 3031 is arranged between rotor 3013and an upper end face of bearing 3024. Compression element 3021 composesa reciprocating type compression mechanism.

Thrust ball bearing 3031 includes: a plurality of balls 3032; holderportion 3033 to hold balls 3032; upper washer 3034 arranged above balls3032; and lower washer 3035 arranged below balls 3032.

Operation of the hermetic compressor composed as described above will beexplained as follows.

When stator 3012 is energized by an external electric power source,rotor 3013 is rotated together with shaft 3022. Due to the foregoing, aneccentric motion is conducted by eccentric shaft portion 3022 c.Therefore, eccentric shaft portion 3022 c reciprocates piston 3025through connecting portion 3026 in compression chamber 3023 a.Accordingly, a predetermined compressive motion to compress suction gasis conducted.

Thrust ball bearing 3031 supports a vertical load generated by the deadweights of rotor 3013 and shaft 3022. Therefore, it is possible toreduce a frictional force generated between rotor 3013 and bearing 3024.Accordingly, an intensity of electric power to be inputted into thehermetic compressor can be decreased and the efficiency can be enhanced.

However, in the above conventional structure, in order to make it easyto assemble the components, thrust ball bearing 3031 is only put on anupper end face of bearing 3024, that is, thrust ball bearing 3031 isarranged without being fixed. Accordingly, there is a possibility thatlower washer 3035 is arranged being shifted at the time of assembling.Further, there is a possibility that lower washer 3035 is shifted by ashock while the device is being conveyed and an inner diameter of lowerwasher 3035 comes into contact with an outer diameter of main shaftportion 3022 which is being rotated.

Concerning lower washer 3035, since a lower face of lower washer 3035 isclosely contacted with an upper end face of bearing 3024 throughviscosity of refrigerating machine oil 3003, lower washer 3035 is notrotated together with balls 3032 and holder portion 3033. Therefore,when an inner diameter of lower washer 3035 comes into contact with anouter diameter of main shaft portion 3022 a which is rotating, abrasionpowder is generated. The thus generated abrasion powder spreads to eachsliding portion of the hermetic compressor and causes abrasion.

DISCLOSURE OF THE INVENTION

A hermetic compressor comprises:

an electrically driving element having stator and a rotor, theelectrically driving element being accommodated in a hermetic container;and

a compression element driven by the electrically driving element, thecompression element being accommodated in the hermetic container,

the compression element comprising:

-   -   a shaft;    -   a cylinder block forming a compression chamber;    -   a bearing for supporting the shaft, arranged in the cylinder        block;    -   a piston reciprocated in the compression chamber;    -   a connecting portion for connecting the piston with an eccentric        shaft portion; and    -   a thrust ball bearing,

the thrust ball bearing comprising:

-   -   a plurality of balls;    -   a holder portion for holding the balls;    -   an upper washer arranged above the balls; and    -   a lower washer arranged below the balls,

the hermetic compressor further comprising a regulation mechanism forregulating the lower washer so that a movable distance in the thrustdirection of the lower washer can be shorter than clearance formedbetween an inner diameter of the lower washer and an outer diameter ofthe main shaft portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 1 of the present invention.

FIG. 2 is an enlarged sectional view showing a primary portion of thehermetic compressor of Embodiment 1 of the present invention.

FIG. 3 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 2 of the present invention.

FIG. 4 is an enlarged sectional view showing a primary portion of thehermetic compressor of Embodiment 2 of the present invention.

FIG. 5 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 3 of the present invention.

FIG. 6 is an enlarged sectional view showing a primary portion of thehermetic compressor of Embodiment 3 of the present invention.

FIG. 7 is a view showing an example of Embodiment 3 of the presentinvention.

FIG. 8 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 4 of the present invention.

FIG. 9 is an enlarged sectional view showing a primary portion of thehermetic compressor of Embodiment 4 of the present invention.

FIG. 10 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 5 of the present invention.

FIG. 11 is an enlarged sectional view showing a primary portion of thehermetic compressor of Embodiment 5 of the present invention.

FIG. 12 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 6 of the present invention.

FIG. 13 is an enlarged sectional view showing a primary portion of thehermetic compressor of Embodiment 6 of the present invention.

FIG. 14 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 7 of the present invention.

FIG. 15 is an enlarged sectional view showing a primary portion of thehermetic compressor of Embodiment 7 of the present invention.

FIG. 16 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 8 of the present invention.

FIG. 17 is an enlarged sectional view showing a primary portion of thehermetic compressor of Embodiment 8 of the present invention.

FIG. 18 is a longitudinal sectional view showing a conventional hermeticcompressor.

FIG. 19 is an enlarged sectional view showing a primary portion of theconventional hermetic compressor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention has been accomplished to solve the above problems.An object of the present invention is to provide a highly reliablehermetic compressor.

In order to solve the above conventional problems, a hermetic compressorof the present invention includes a regulation means, which is arrangedbetween a lower washer and an upper end face of a bearing, forregulating the lower washer so that a movable distance in the thrustdirection of the lower washer can be shorter than clearance between aninner diameter of the lower washer and an outer diameter of a main shaftportion. Due to the above structure, the inner diameter of the lowerwasher can be prevented from coming into contact with the outer diameterof the main shaft portion. Therefore, the generation of abrasion powdercan be prevented.

In the hermetic compressor of the present invention, the generation ofabrasion powder can be prevented. Therefore, it is possible to provide ahighly reliable hermetic compressor.

Referring to the drawings, embodiments of the present invention will beexplained below. In this connection, it should be noted that the presentinvention is not limited to this specific embodiment.

Embodiment 1

FIG. 1 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 1 of the present invention. FIG. 2 is an enlarged sectionalview showing a primary portion of the hermetic compressor of Embodiment1 of the present invention.

In FIGS. 1 and 2, refrigerant 1102 is charged into hermetic container1101. Further, refrigerating machine oil 1103 is stored in hermeticcontainer 1101. In this case, refrigerant 1102 is R600a which is ahydrocarbon refrigerant. Refrigerating machine oil 1103 is an oil, whichis compatible with refrigerant 1102, such as synthetic fluid, mineraloil or polyol ester oil.

Electric driving element 1111 includes: stator 1112 connected to anexternal electric power source (not shown); and rotor 1113 arranged,forming a predetermined gap between rotor 1113 and stator 1112.

Compression element 1121 includes: shaft 1122; cylinder block 1123;bearing 1124; piston 1125; connecting portion 1126; and thrust ballbearing 1131. Shaft 1122 includes: main shaft portion 1122 a, the outerdiameter of which is d; and eccentric shaft portion 1122 c formed out ofmain shaft portion 1122 a through flange portion 1122 b. Cylinder block1123 composes compression chamber 1123 a. Bearing 1124 supports shaft1122 provided in cylinder block 1123. Piston 1125 reciprocates incompression chamber 1123 a. Connecting portion 1126 connects piston 1125with eccentric shaft portion 1122 c. Thrust ball bearing 1131 isarranged between flange portion 1122 b and an upper end face of bearing1124. Compression element 1121 composes a reciprocating type compressionmechanism.

Rotor 1113 is engaged with main shaft portion 1122 a of the shaft.Stator 1112 is arranged and fixed in a lower portion of cylinder block1123.

Thrust ball bearing 1131 includes: a plurality of balls 1132; holderportion 1133 for holding balls 1132; upper washer 1134 arranged aboveballs 1132; and lower washer 1135, the outer diameter of which is b andthe inner diameter of which is C, arranged below balls 1132. In cylinderblock 1123, at a height in which lower washer 1135 is arranged, firstcylindrical wall 1141, the inner diameter of which is A, surrounding theoutside of lower washer 1135, is arranged. It is composed so thatclearance (A−b)/2 between outer diameter b of lower washer 1135 andinner diameter A of first cylinder wall 1141 can be smaller thanclearance (C−d)/2 between inner diameter C of lower washer 1135 andouter diameter d of main shaft portion 1122 a.

Operation and action of the hermetic compressor composed as describedabove will be explained below.

When stator 1112 is energized by an external electric power source (notshown), rotor 1113 is rotated together with shaft 1122. Due to theforegoing, an eccentric motion is conducted by eccentric shaft portion1122 c. Therefore, eccentric shaft portion 1122 c reciprocates piston1125 through connecting portion 1126 in compression chamber 1123 a.Accordingly, a predetermined compressive motion to compress suction gasis conducted.

At this time, balls 1132 of thrust ball bearing 1131 support a verticalload generated by the dead weights of rotor 1113 and shaft 1122. Anupper surface of upper washer 1134 is closely contacted with a lowersurface of flange portion 1122 b of shaft 1122 through viscosity ofrefrigerating machine oil 1103. Therefore, when shaft 1122 is rotated,upper washer 1134 is rotated synchronously with shaft 1122. On the otherhand, a lower surface of lower washer 1135 is also closely contactedwith an upper end portion of bearing 1124 through viscosity ofrefrigerating machine oil 1103. Therefore, lower washer 1135 is notrotated. Since slippage is generated between rotating balls 1132 andlower washer 1135, balls 1132 and holder portion 1133 are rotated beingdelayed without following a rotation of shaft 1122. In general, thecoefficient of rolling friction is 10 to 20 times as low as thecoefficient of sliding friction. Further, no metal contact is caused inthe rolling bearing. Therefore, it is possible to conduct a stablemotion by the rolling bearing.

In this structure, clearance (A−b)/2 between outer diameter b of lowerwasher 1135 and inner diameter A of first cylinder wall 1141 is smallerthan clearance (C−d)/2 between inner diameter C of lower washer 1135 andouter diameter d of main shaft portion 1122 a. Accordingly, before lowerwasher 1135 comes into contact with main shaft portion 1122 a, an outerdiameter of lower washer 1135 and an inner diameter of cylindrical wall1141 are contacted with each other. That is, by first cylindrical wall1141 surrounding the outside of lower washer 1135, the inner diameter oflower washer 1135 is arranged at a position where the inner diameter oflower washer 1135 does not come into contact with the outer diameter ofmain shaft portion 1122 a.

When first cylindrical wall 1141 surrounding the outside of lower washer1135 is provided in cylinder block 1123 or bearing 1124 as describedabove, a regulation mechanism is formed.

Consequently, according to the present embodiment, the inner diameter oflower washer 1135 can be prevented from coming into contact with theouter diameter of main shaft portion 1122 a by this regulationmechanism. Accordingly, there is no possibility that lower washer 1135damages main shaft portion 1122 a and generates abrasion powder.Therefore, it is possible to realize a highly reliable hermeticcompressor.

Since first cylindrical wall 1141 can be manufactured simultaneouslywhen cylinder block 1123 or bearing 1124 is machined, it is unnecessaryto add a new component. Therefore, the productivity can be enhanced.

Further, since thrust ball bearing 1131 can be incorporated into thedevice only when it is accommodated in first cylindrical wall 1141 withshaft 1122 being inserted into the thrust ball bearing at the time ofassembling, it is unnecessary to use a special assembling method such asa method of press-fitting lower washer 1135. Accordingly, the workingproperty can be enhanced at the time of assembling.

In this connection, in the present embodiment, first cylindrical wall1141 is integrated with cylinder block 1123 into one body. However, ofcourse, it is possible to provide the same effect even when firstcylindrical wall 1141 is integrated with bearing 1124 into one body.

Embodiment 2

FIG. 3 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 2 of the present invention. FIG. 4 is an enlarged sectionalview showing a primary portion of the hermetic compressor of Embodiment2 of the present invention.

Like reference characters are used to indicate like parts in Embodiments1 and 2.

In FIGS. 3 and 4, refrigerant 1102 is charged into hermetic container1101. Further, refrigerating machine oil 1103 is stored in hermeticcontainer 1101. In this case, refrigerant 1102 is R600a which is ahydrocarbon refrigerant. Refrigerating machine oil 1103 is an oil, whichis compatible with refrigerant 1102, such as synthetic fluid, mineraloil or polyol ester oil.

Electric driving element 1111 includes: stator 1112 connected to anexternal electric power source (not shown); and rotor 1113 arranged,forming a predetermined gap between rotor 1113 and stator 1112.

Compression element 1221 includes: shaft 1122; cylinder block 1123;bearing 1224; piston 1125; connecting portion 1126; and thrust ballbearing 1231. Shaft 1122 includes: main shaft portion 1122 a, the outerdiameter of which is d; and eccentric shaft portion 1122 c formed out ofmain shaft portion 1122 a through flange portion 1122 b. Cylinder block1123 is fixed in a portion above stator 1112 and composes compressionchamber 1123 a. Bearing 1224 supports shaft 1122 provided in cylinderblock 1123. Piston 1125 reciprocates in compression chamber 1123 a.Connecting portion 1126 connects piston 1125 with eccentrics haftportion 1122 c. Thrust ball bearing 1231 is arranged between flangeportion 1122 b and an upper end face of bearing 1224. Compressionelement 1221 composes a reciprocating type compression mechanism.

Rotor 1113 is engaged with main shaft portion 1122 a of the shaft.Stator 1112 is arranged and fixed in a lower portion of cylinder block1123.

Thrust ball bearing 1231 includes: a plurality of balls 1232; holderportion 1233 for holding balls 1232; upper washer 1234 arranged aboveballs 1232; and lower washer 1235, the outer diameter of which is b andthe inner diameter of which is C, arranged below the balls 1232. Onlower washer 1235, first recess portion 1241 is provided. On an upperend face of bearing 1224, first protruding portion 1242 is provided.First recess portion 1241 and first protruding portion 1242 are idlyengaged with each other. It is composed so that Clearance (E−f)/2 in thethrust direction between width E in the thrust direction of first recessportion 1241 and width f in the thrust direction of first protrudingportion 1242 can be smaller than clearance (C−d)/2 between innerdiameter C of lower washer 1235 and outer diameter d of main shaftportion 1122 a.

Operation and action of the hermetic compressor composed as describedabove will be explained below.

When stator 1112 is energized by an external electric power source (notshown), rotor 1113 is rotated together with shaft 1122. Due to theforegoing, an eccentric motion is conducted by eccentric shaft portion1122 c. Therefore, eccentric shaft portion 1122 c reciprocates piston1125 through connecting portion 1126 in compression chamber 1123 a.Accordingly, a predetermined compressive motion to compress suction gasis conducted.

At this time, balls 1232 of thrust ball bearing 1231 support a verticalload generated by the dead weights of rotor 1113 and shaft 1122. Anupper surface of upper washer 1234 is closely contacted with a lowersurface of flange portion 1122 b of shaft 1122 through viscosity ofrefrigerating machine oil 1103. Therefore, when shaft 1122 is rotated,upper washer 1234 is rotated synchronously with shaft 1122. On the otherhand, a lower surface of lower washer 1235 is also closely contactedwith an upper end portion of bearing 1224 through viscosity ofrefrigerating machine oil 1103. Therefore, lower washer 1235 is notrotated. Slippage is generated between rotating balls 1232 and lowerwasher 1235. Therefore, balls 1232 and holder portion 1233 are rotatedbeing delayed without following a rotation of shaft 1122. In general,the coefficient of rolling friction is 10 to 20 times as low as thecoefficient of sliding friction. Further, no metal contact is caused inthe rolling bearing. Therefore, it is possible to conduct a stablemotion by the rolling bearing.

Clearance (E−f)/2 in the thrust direction between width E in the thrustdirection of first recess portion 1241 and width f in the thrustdirection of first protruding portion 1242 is smaller than clearance(C−d)/2 between inner diameter C of lower washer 1235 and outer diameterd of main shaft portion 1122 a. Therefore, before lower washer 1235comes into contact with main shaft portion 1122 a, an end face of firstrecess portion 1241 and an end face of first protruding portion 1242come into contact with each other. That is, by first recess portion 1241and first protruding portion 1242, the inner diameter of lower washer1235 is surely arranged at a position where it can not be contacted withthe outer diameter of rotating main shaft portion 1122 a. Therefore,according to the present embodiment, there is no possibility that theinner diameter of lower washer 1235 comes into contact with the outerdiameter of main shaft portion 1122 a.

As described above, on lower washer 1235, first recess portion 1241 isprovided. On the upper end face of bearing 1224, first protrudingportion 1242 is provided. First recess portion 1241 and first protrudingportion 1242 are idly engaged with each other. In this way, a regulationmechanism is formed.

According to the present embodiment, by this regulation mechanism, theinner diameter of lower washer 1235 can be prevented from coming intocontact with the outer diameter of main shaft portion 1122 a.Accordingly, there is no possibility that lower washer 1235 damages mainshaft portion 1122 a and generates abrasion powder. Therefore, it ispossible to realize a highly reliable hermetic compressor.

First recess portion 1241 can be formed, for example, simultaneouslywhen lower washer 1235 is formed by means of press forming. Firstprotruding portion 1242 can be formed, for example, simultaneously whenbearing 1242 is molded by means of die-cast molding. Therefore, it isunnecessary to add a manufacturing step. Accordingly, it is possible toenhance the productivity of producing a hermetic compressor.

Since thrust ball bearing 1231 can be incorporated into the device onlywhen shaft 1122 is inserted into the thrust ball bearing and firstrecess portion 1241 and first protruding portion 1242 are idly engagedwith each other at the time of assembling, it is unnecessary to use aspecial assembling method such as a method of press-fitting lower washer1135. Accordingly, the working property of assembling can be enhanced.

In the present embodiment, first recess portion 1241 is a hollow portionwhich does not penetrate lower washer 1235. However, as long as firstprotruding portion 1242 does not exceed the wall thickness of lowerwasher 1235 and first recess portion 1241 is out of the rotary locus ofballs 1232 controlled by holder portion 1233, of course, first recessportion 1241 can provide the same operational effect as that of a holepenetrating lower washer 1235.

In the present embodiment, first recess portion 1241 is a hollow portionnot penetrating lower washer 1235. However, as long as first protrudingportion 1242 is out of the rotary locus of balls 1232 controlled byholder portion 1233 and first protruding portion 1242 is arranged in arange in which first protruding portion 1242 can not obstruct rotatingballs 1232, of course, the same operational effect can be provided evenwhen first recess portion 1241 is a hole penetrating lower washer 1235and first protruding portion 1242 exceeds the wall thickness of lowerwasher 1235.

Embodiment 3

FIG. 5 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 3 of the present invention. FIG. 6 is an enlarged sectionalview showing a primary portion of the hermetic compressor of Embodiment3 of the present invention. FIG. 7 is a view showing an example ofEmbodiment 3 of the present invention.

Like reference characters are used to indicate like parts in Embodiments1 and 3.

In FIGS. 5 and 6, refrigerant 1102 is charged into hermetic container1101. Further, refrigerating machine oil 1103 is stored in hermeticcontainer 1101. In this case, refrigerant 1102 is R600a which is ahydrocarbon refrigerant. Refrigerating machine oil 1103 is an oil, whichis compatible with refrigerant 1102, such as synthetic fluid, mineraloil or polyol ester oil.

Electric driving element 1111 includes: stator 1112 connected to anexternal electric power source (not shown); and rotor 1113 arranged,forming a predetermined gap between rotor 1113 and stator 1112.

Compression element 1321 includes: shaft 1122; cylinder block 1123;bearing 1324; piston 1125; connecting portion 1126; and thrust ballbearing 1331. Shaft 1122 includes: main shaft portion 1122 a, the outerdiameter of which is d; and eccentric shaft portion 1122 c formed out ofmain shaft portion 1122 a through flange portion 1122 b. Cylinder block1123 is fixed in a portion above stator 1112 and composes compressionchamber 1123 a. Bearing 1324 supports shaft 1122 provided in cylinderblock 1123. Piston 1125 reciprocates in compression chamber 1123 a.Connecting portion 1126 connects piston 1125 with eccentric shaftportion 1122 c. Thrust ball bearing 1331 is arranged between flangeportion 1122 b and an upper end face of bearing 1124. Compressionelement 1321 composes a reciprocating type compression mechanism.

Rotor 1113 is engaged with main shaft portion 1122 a of the shaft.Stator 1112 is arranged and fixed in a lower portion of cylinder block1123.

Thrust ball bearing 1331 includes: a plurality of balls 1332; holderportion 1333 for holding balls 1332; upper washer 1334 arranged aboveballs 1332; and lower washer 1335, the outer diameter of which is b andthe inner diameter of which is C, arranged below balls 1332. On an outercircumference of lower washer 1335, first bent portion 1341 is formed.It is composed so that clearance (J−k)/2 in the thrust direction betweeninner circumferential diameter J of first bent portion 1341 and outerdiameter k of bearing 1324 can be smaller than clearance (C−d)/2 betweeninner diameter C of lower washer 1335 and outer diameter d of main shaftportion 1122 a.

Operation and action of the hermetic compressor composed as describedabove will be explained below.

When stator 1112 is energized by an external electric power source (notshown), rotor 1113 is rotated together with shaft 1122. Due to theforegoing, an eccentric motion is conducted by eccentric shaft portion1122 c. Therefore, eccentric shaft portion 1122 c reciprocates piston1125 through connecting portion 1126 in compression chamber 1123 a.Accordingly, a predetermined compressive motion to compress suction gasis conducted.

At this time, balls 1332 of thrust ball bearing 1331 support a verticalload generated by the dead weights of rotor 1113 and shaft 1122. Anupper surface of upper washer 1334 is closely contacted with a lowersurface of flange portion 1122 b of shaft 1122 through viscosity ofrefrigerating machine oil 1103. Therefore, when shaft 1122 is rotated,upper washer 1334 is rotated synchronously with shaft 1122. On the otherhand, a lower surface of lower washer 1335 is also closely contactedwith an upper end portion of bearing 1324 through viscosity ofrefrigerating machine oil 1103. Therefore, lower washer 1335 is notrotated. Since slippage is generated between rotating balls 1332 andlower washer 1335. Therefore, balls 1332 and holder portion 1333 arerotated being delayed without following a rotation of shaft 1122. Ingeneral, the coefficient of rolling friction is 10 to 20 times as low asthe coefficient of sliding friction. Further, no metal contact is causedin the rolling bearing. Therefore, it is possible to conduct a stablemotion by the rolling bearing.

It is composed so that clearance (J−k)/2 in the thrust direction betweeninner circumferential diameter J of first bent portion 1341 and outerdiameter k of bearing 1324 can be smaller than clearance (C−d)/2 betweeninner diameter C of lower washer 1335 and outer diameter d of main shaftportion 1122 a. Accordingly, before lower washer 1135 comes into contactwith main shaft portion 1122 a, the inner circumferential diameter offirst bent portion 1341 and the outer diameter of bearing 1324 come intocontact with each other. That is, by first bent portion 1341, lowerwasher 1335 is surely arranged at a position where the inner diameter oflower washer 1335 does not come into contact with the outer diameter ofrotating main shaft portion 1122 a.

When first bent portion 1341 or raised portions 1342 is provided on theouter circumference of lower washer 1335 as described above, aregulation mechanism is composed.

Therefore, according to the present embodiment, the inner diameter oflower washer 1335 can be prevented from coming into contact with theouter diameter of main shaft portion 1122 a by this regulationmechanism. Accordingly, there is no possibility that main shaft portion1122 a is damaged by lower washer 1335 and abrasion powder is generated.Therefore, it is possible to realize a highly reliable hermeticcompressor.

First bent portion 1341 can be formed, for example, simultaneously whenlower washer 1335 is formed by means of press forming. Therefore, it isunnecessary to add a manufacturing step and it is possible to enhancethe productivity of a hermetic compressor.

Concerning thrust ball bearing 1331, only when shaft 1122 is insertedinto thrust ball bearing 1331 and first bent portion 1341 is idlyengaged with bearing 1324 at the time of assembling, it is possible toincorporate thrust ball bearing 1331. That is, it is unnecessary to usea special assembling method such as press-fitting lower washer 1335.Accordingly, the property of assembling work can be enhanced.

In this connection, in the present embodiment, first bent portion 1341is formed into a shape in which an overall circumference of lower washer1335 is subjected to extrusion. However, of course, the same operationaleffect can be provided when three or more raised portions 1342 areprovided on the outer circumference of lower washer 1335 as shown inFIG. 7.

Embodiment 4

FIG. 8 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 4 of the present invention. FIG. 9 is an enlarged sectionalview showing a primary portion of the hermetic compressor of Embodiment4 of the present invention.

In this connection, like reference characters are used to indicate likeparts in Embodiments 1 and 4.

In FIGS. 8 and 9, refrigerant 1102 is charged into hermetic container1101. Further, refrigerating machine oil 1103 is stored in hermeticcontainer 1101. In this case, refrigerant 1102 is R600a which is ahydrocarbon refrigerant. Refrigerating machine oil 1103 is an oil, whichis compatible with refrigerant 1102, such as synthetic fluid, mineraloil or polyol ester oil.

Electric driving element 1111 includes: stator 1112 connected to anexternal electric power source (not shown); and rotor 1113 arranged,forming a predetermined gap between rotor 1113 and stator 1112.

Compression element 1421 includes: shaft 1122; cylinder block 1123;bearing 1424; piston 1125; connecting portion 1126; and thrust ballbearing 1431. Shaft 1122 includes: main shaft portion 1122 a; andeccentric shaft portion 1122 c formed out of main shaft portion 1122 athrough flange portion 1122 b. Cylinder block 1123 is fixed in a portionabove stator 1112 and composes compression chamber 1123 a. Bearing 1424supports shaft 1122 provided in cylinder block 1123. Piston 1125reciprocates in compression chamber 1123 a. Connecting portion 1126connects piston 1125 with eccentric shaft portion 1122 c. Thrust ballbearing 1431 is arranged between flange portion 1122 b and an upper endface of bearing 1424. Compression element 1421 composes a reciprocatingtype compression mechanism.

Rotor 1113 is engaged with main shaft portion 1122 a of the shaft.Stator 1112 is arranged and fixed in a lower portion of cylinder block1123.

Thrust ball bearing 1431 includes: a plurality of balls 1432; holderportion 1433 for holding balls 1432; upper washer 1434 arranged aboveballs 1432; and lower washer 1435, arranged below balls 1432. In bearing1424, at the height in which lower washer 1435 is arranged, firstannular protruding portion 1441, which is surrounded by the inside ofthe lower washer, is provided. Therefore, under the condition that thelower surface of lower washer 1435 is closely contacted with an upperend face of bearing 1424, an inner diameter of lower washer 1435 can notbe moved inside from first annular protruding portion 1441.

Operation and action of the hermetic compressor composed as describedabove will be explained below.

When stator 1112 is energized by an external electric power source (notshown), rotor 1113 is rotated together with shaft 1122. Due to theforegoing, an eccentric motion is conducted by eccentric shaft portion1122 c. Therefore, eccentric shaft portion 1122 c reciprocates piston1125 through connecting portion 1126 in compression chamber 1123 a.Accordingly, a predetermined compressive motion to compress suction gasis conducted.

At this time, balls 1432 of thrust ball bearing 1431 support a verticalload generated by the dead weights of rotor 1113 and shaft 1122. Anupper surface of upper washer 1434 is closely contacted with a lowersurface of flange portion 1122 b of shaft 1122 through viscosity ofrefrigerating machine oil 1103. Therefore, when shaft 1122 is rotated,upper washer 1434 is rotated synchronously with shaft 1122. On the otherhand, a lower surface of lower washer 1435 is also closely contactedwith an upper end portion of bearing 1424 through viscosity ofrefrigerating machine oil 1103. Therefore, lower washer 1435 is notrotated. Slippage is generated between rotating balls 1432 and lowerwasher 1435. Therefore, balls 1432 and holder portion 1433 are rotatedbeing delayed without following a rotation of shaft 1122. In general,the coefficient of rolling friction is 10 to 20 times as low as thecoefficient of sliding friction. Further, no metal contact is caused inthe rolling bearing. Therefore, it is possible to conduct a stablemotion by the rolling bearing.

Since first annular protruding portion 1441 exists between an innerdiameter of lower washer 1435 and an outer diameter of main shaftportion 1122 a, the inner diameter of lower washer 1435 comes intocontact with first annular protruding portion 1441 before it comes intocontact with the outer diameter of main shaft portion 1122 a. That is,by first annular protruding portion 1441, the inner diameter of lowerwasher 1435 is surely arranged at a position where the inner diameter oflower washer 1435 does not come into contact with the outer diameter ofrotating main shaft portion 1122 a.

As described above, a regulation mechanism is composed when firstannular protruding portion 1441 is provided inside the upper end face ofbearing 1424.

Therefore, according to the present embodiment, the inner diameter oflower washer 1435 can be prevented from coming into contact with theouter diameter of main shaft portion 1122 a by this regulationmechanism. Accordingly, there is no possibility that main shaft portion1122 a is damaged by lower washer 1435 and abrasion powder is generated.Therefore, it is possible to realize a highly reliable hermeticcompressor.

First annular protruding portion 1441 can be formed, for example,simultaneously when bearing 1424 is molded by means of die-cast molding.Therefore, it is unnecessary to add a manufacturing step. Accordingly,it is possible to enhance the productivity of producing a hermeticcompressor.

Since thrust ball bearing 1431 can be incorporated into the device onlywhen shaft 1122 is inserted into the thrust ball bearing and the innerdiameter of lower washer 1435 is idly engaged with the outer diameter offirst annular protruding portion 1441, it is unnecessary to use aspecial assembling method such as a method of press-fitting lower washer1435. Accordingly, the working property can be enhanced at the time ofassembling.

In this connection, in the present embodiment, first annular protrudingportion 1441 is arranged at a height in which lower washer 1435 isarranged. However, as long as first annular protruding portion 1441 isout of the rotary locus of balls 1432 controlled by holder portion 1433and as long as first annular protruding portion 1441 is arranged in arange in which the rotation of balls 1432 is not obstructed, even whenfirst annular protruding portion 1441 exceeds the wall thickness oflower washer 1435, the same operational effect can be provided.

Embodiment 5

FIG. 10 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 5 of the present invention. FIG. 11 is an enlarged sectionalview showing a primary portion of the hermetic compressor of Embodiment5 of the present invention.

In FIGS. 10 and 11, refrigerant 2102 is charged into hermetic container2101. Further, refrigerating machine oil 2103 is stored in hermeticcontainer 2101. In this case, refrigerant 2102 is R600a which is ahydrocarbon refrigerant. Refrigerating machine oil 2103 is an oil, whichis compatible with refrigerant 2102, such as synthetic fluid, mineraloil or polyol ester oil.

Electric driving element 2111 includes: stator 2112 connected to anexternal electric power source (not shown); and rotor 2113 arranged,forming a predetermined gap between rotor 2113 and stator 2112.

Compression element 2121 includes: shaft 2122; cylinder block 2123;bearing 2124; piston 2125; connecting portion 2126; and thrust ballbearing 2131. Shaft 2122 includes: main shaft portion 2122 a, the outerdiameter of which is d; and eccentric shaft portion 2122 c connected tomain shaft portion 2122 a. Cylinder block 2123 composes compressionchamber 2123 a. Bearing 2124 supports shaft 2122, and is provided beingintegrated with or separated from cylinder block 2123. Piston 2125reciprocates in compression chamber 2123 a. Connecting portion 2126connects piston 2125 with eccentric shaft portion 2122 c. Thrust ballbearing 2131 is arranged between an upper end face of bearing 2124 androtor 2113 fixed to main shaft portion 2122 a. Compression element 2121composes a reciprocating type compression mechanism.

Rotor 2113 is engaged with main shaft portion 2122 a of the shaft.Stator 2112 is arranged and fixed in an upper portion of cylinder block2123.

Thrust ball bearing 2131 includes: a plurality of balls 2132; holderportion 2133 for holding balls 2132; upper washer 2134 arranged aboveballs 2132; and lower washer 2135 arranged below balls 2132.

In bearing 2124, at the height in which lower washer 2135 is arranged,second cylindrical wall 2141 surrounding the outside of lower washer2135 is provided. It is composed so that clearance A between the outerdiameter of lower washer 2135 and the inner diameter of secondcylindrical wall 2141 can be smaller than clearance c between the innerdiameter of lower washer 2135 and the outer diameter of main shaftportion 2122 a.

Since lower washer 2135 is made of carbon steel of not less than 70%,the hardness of lower washer 2135 is made to be about 95% of thehardness of balls 2132 of thrust ball bearing 2131. On rolling face 2136with which balls 2132 comes into contact, flatness is maintained to benot more than 30 microns. Further, when rolling face 2136 is subjectedto quenching, predetermined hardness can be ensured.

In the present embodiment, second cylindrical wall 2141 surrounding theoutside is formed in such a manner that a stainless steel sheet isformed into a cylindrical shape. This second cylindrical wall 2141 isengaged with an outer circumference of an upper portion of bearing 2124.When the inner diameter of the cylindrical shape of second cylindricalwall 2141 is made to be a little smaller than the outer diameter of theouter circumference of the upper portion of bearing 2124, secondcylindrical wall 2141 is fixed onto the outer circumference of the upperportion of bearing 2124 by an elastic force generated by secondcylindrical wall 2141 itself at the time of engagement.

Operation and action of the hermetic compressor composed as describedabove will be explained below.

When stator 2112 is energized by an external electric power source (notshown), rotor 2113 is rotated together with shaft 2122. Due to theforegoing, an eccentric motion is conducted by eccentric shaft portion2122 c. Therefore, eccentric shaft portion 2122 c reciprocates piston2125 through connecting portion 2126 in compression chamber 2123 a.Accordingly, a predetermined compressive motion to compress suction gasis conducted.

At this time, balls 2132 of thrust ball bearing 2131 support a verticalload generated by the dead weights of rotor 2113 and shaft 2122. Anupper surface of upper washer 2134 is closely contacted with a lower endsurface of rotor 2113 fixed to main shaft portion 2122 a throughviscosity of refrigerating machine oil 2103. Therefore, when shaft 2122is rotated, upper washer 2134 is rotated synchronously with shaft 2122.On the other hand, a lower surface of lower washer 2135 is also closelycontacted with an upper end portion of bearing 2124 through viscosity ofrefrigerating machine oil 2103. Therefore, lower washer 2135 is notrotated. Since slippage is generated between rotating balls 2132 andlower washer 2135, balls 2132 and holder portion 2133 are rotated beingdelayed without following a rotation of shaft 2122. In general, thecoefficient of rolling friction is 10 to 20 times as low as thecoefficient of sliding friction. Further, no metal contact is caused inthe rolling bearing. Therefore, it is possible to conduct a stablemotion by the rolling bearing.

Clearance A between the outer diameter of lower washer 2135 and theinner diameter of second cylindrical wall 2141 is smaller than clearancec between the inner diameter of lower washer 2135 and the outer diameterof main shaft portion 2122 a. Accordingly, before lower washer 2135comes into contact with main shaft portion 2122 a, the outer diameter oflower washer 2135 and the inner diameter of second cylindrical wall 2141come into contact with each other. That is, by second cylindrical wall2141 surrounding the outside of lower washer 2135, the inner diameter oflower washer 2135 is arranged at a position where the inner diameter oflower washer 2135 does not come into contact with the outer diameter ofrotating main shaft portion 2122 a.

When second cylindrical wall 2141 surrounding the outside of lowerwasher 2135 is provided in an upper portion of bearing 2124, aregulation mechanism is composed.

Therefore, according to the present embodiment, the inner diameter oflower washer 2135 can be prevented from coming into contact with theouter diameter of main shaft portion 2122 a by this regulationmechanism. Accordingly, there is no possibility that main shaft portion2122 a is damaged by lower washer 2135 and abrasion powder is generated.Therefore, it is possible to realize a highly reliable hermeticcompressor.

Since it is composed in such a manner that second cylindrical wall 2141is formed out of a substantially annular sheet member and lightlypress-fitted into the outer diameter of bearing 2124, a size of secondcylindrical wall 2141 is formed to be substantially the same as that ofthe outer diameter of bearing 2124. Therefore, these components arearranged in the minimized space. Accordingly, there is no possibilitythat second cylindrical wall 2141 interferes with other parts even whenrotor 2113 exists in the periphery of bearing 2124.

Concerning thrust ball bearing 2131, only when shaft 2122 is insertedinto thrust ball bearing 2131 at the time of assembling and the outerdiameter of lower washer 2135 is accommodated in second cylindrical wall2141, a regulation means can be easily provided. Therefore, it isunnecessary to use a special assembling method of press-fitting lowerwasher 2135. Accordingly, the assembling work property can be enhanced.

In this connection, in the present embodiment, second cylindrical wall2141 is formed out of a substantially annular sheet which is formeddifferently from bearing 2124. However, of course, when secondcylindrical wall 2141 is formed being integrated with bearing 2124 intoone body, the same effect can be provided.

Embodiment 6

FIG. 12 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 6 of the present invention. FIG. 13 is an enlarged sectionalview showing a primary portion of the hermetic compressor of Embodiment6 of the present invention.

In FIGS. 12 and 13, refrigerant 2202 is charged into hermetic container2201. Further, refrigerating machine oil 2203 is stored in hermeticcontainer 2201. In this case, refrigerant 2202 is R600a which is ahydrocarbon refrigerant. Refrigerating machine oil 2203 is an oil, whichis compatible with refrigerant 2202, such as synthetic fluid, mineraloil or polyol ester oil.

Electric driving element 2211 includes: stator 2212 connected to anexternal electric power source (not shown); and rotor 2213 arranged,forming a predetermined gap between rotor 2213 and stator 2212.

Compression element 2221 includes: shaft 2222; cylinder block 2223;bearing 2224; piston 2225; connecting portion 2226; and thrust ballbearing 2231. Shaft 2222 includes: main shaft portion 2222 a, the outerdiameter of which is d; and eccentric shaft portion 2222 c connected tomain shaft portion 2222 a. Cylinder block 2223 composes compressionchamber 2223 a. Bearing 2224 supports shaft 2222, and is provided beingintegrated with cylinder block 2223 or being separated from cylinderblock 2223. Piston 2225 reciprocates in compression chamber 2223 a.Connecting portion 2226 connects piston 2225 with eccentric shaftportion 2222 c. Thrust ball bearing 2231 is arranged between the upperend face of bearing 2224 and rotor 2213 fixed to main shaft portion 2222a. Compression element 2221 composes a reciprocating type compressionmechanism.

Rotor 2213 is engaged with main shaft portion 2222 a of the shaft.Stator 2212 is arranged and fixed in an upper portion of cylinder block2223.

Thrust ball bearing 2231 includes: a plurality of balls 2232; holderportion 2233 for holding balls 2232; upper washer 2234 arranged aboveballs 2232; and lower washer 2235, the inner diameter of which is C,arranged below the balls 2232. On lower washer 2235, second recessportion 2241 is provided. On the upper end face of bearing 2224, secondprotruding portion 2242 is provided. These second recess portion 2241and second protruding portion 2242 are idly engaged with each other. Itis composed in such a manner that clearance (E−f)/2 in the thrustdirection between width E in the thrust direction of the second recessportion 2241 and width f in the thrust direction of second protrudingportion 2242 is smaller than clearance (C−d)/2 between inner diameter Cof lower washer 2235 and outer diameter d of main shaft portion 2222 a.

Since lower washer 2235 is made of carbon steel of not less than 70%,the hardness of lower washer 2235 is made to be about 95% of thehardness of balls 2232 of thrust ball bearing 2231. On rolling face 2236with which balls 2232 comes into contact, flatness is maintained to benot more than 30 microns. Further, when rolling face 2236 is subjectedto quenching, predetermined hardness can be ensured.

Operation and action of the hermetic compressor composed as describedabove will be explained below.

When stator 2212 is energized by an external electric power source (notshown), rotor 2213 is rotated together with shaft 2222. Due to theforegoing, an eccentric motion is conducted by eccentric shaft portion2222 c. Therefore, eccentric shaft portion 2222 c reciprocates piston2225 through connecting portion 2226 in compression chamber 2223 a.Accordingly, a predetermined compressive motion to compress suction gasis conducted.

At this time, balls 2232 of thrust ball bearing 2231 support a verticalload generated by the dead weights of rotor 2213 and shaft 2222. Anupper surface of upper washer 2234 is closely contacted with a lowersurface of rotor 2213 fixed to main shaft portion 2222 a throughviscosity of refrigerating machine oil 2203. Therefore, when shaft 2222is rotated, upper washer 2234 is rotated synchronously with shaft 2222.On the other hand, a lower surface of lower washer 2235 is also closelycontacted with an upper end portion of bearing 2224 through viscosity ofrefrigerating machine oil 2203. Therefore, lower washer 2235 is notrotated. Since slippage is generated between rotating balls 2232 andlower washer 2235, balls 2232 and holder portion 2233 are rotated beingdelayed without following a rotation of shaft 2222. In general, thecoefficient of rolling friction is 10 to 20 times as low as thecoefficient of sliding friction. Further, no metal contact is caused inthe rolling bearing. Therefore, it is possible to conduct a stablemotion by the rolling bearing.

Clearance (E−f)/2 in the thrust direction between width E in the thrustdirection of second recess portion 2241 and width f in the thrustdirection of second protruding portion 2242 is smaller than clearance(C−d)/2 between inner diameter C of lower washer 2235 and outer diameterd of main shaft portion 2222 a. Therefore, before lower washer 2235comes into contact with main shaft portion 2222 a, an end face of secondrecess portion 2241 and an end face of second protruding portion 2242come into contact with each other. That is, by second recess portion2241 and second protruding portion 2242, the inner diameter of lowerwasher 2235 is surely arranged at a position where the inner diameter oflower washer 2235 does not come into contact with the outer diameter ofrotating main shaft portion 2222 a. Therefore, according to the presentembodiment, there is no possibility that the inner diameter of lowerwasher 2235 comes into contact with the outer diameter of main shaftportion 2222 a.

As described above, when second recess portion 2241 and secondprotruding portion 2242, which are idly engaged with each other, arerespectively provided on lower washer 2235 and the upper end face ofbearing 2224, a regulation mechanism is composed.

Therefore, according to the present embodiment, the inner diameter oflower washer 2235 can be prevented from coming into contact with theouter diameter of main shaft portion 2222 a by this regulationmechanism. Accordingly, there is no possibility that main shaft portion2222 a is damaged by the lower washer 2235 and abrasion powder isgenerated. Therefore, it is possible to realize a highly reliablehermetic compressor.

Second recess portion 2241 can be formed, for example, simultaneouslywhen lower washer 2235 is formed by means of press forming. Secondprotruding portion 2242 can be formed, for example, simultaneously whenbearing 2242 is molded by means of die-cast molding. Therefore, it isunnecessary to add a new manufacturing step. Accordingly, it is possibleto enhance the productivity of producing a hermetic compressor.

Since thrust ball bearing 2231 can be incorporated into the device onlywhen shaft 2122 is inserted into the thrust ball bearing and when secondrecess portion 2241 and second protruding portion 2242 are put on eachother and the lower washer is arranged on the upper end face of thebearing at the time of assembling, it is unnecessary to use a specialassembling method such as a method of press-fitting lower washer 2235.Accordingly, the working property can be enhanced at the time ofassembling.

In the present embodiment, second recess portion 2241 is a hollowportion which does not penetrate lower washer 2235. However, as long assecond protruding portion 2242 does not exceed the wall thickness oflower washer 2235 and second recess portion 2241 is out of the rotarylocus of balls 2232 controlled by holder portion 2233, of course, secondrecess portion 2241 can provide the same operational effect as that of astructure in which the second recess portion 2241 is formed into a holepenetrating lower washer 2235.

In the present embodiment, second recess portion 2241 is a hollowportion not penetrating lower washer 2235. However, as long as secondprotruding portion 2242 is out of the rotary locus of balls 2232controlled by holder portion 2233 and second protruding portion 2242 isarranged in a range in which second protruding portion 2242 can notobstruct rotating balls 2232, of course, the same operational effect canbe provided even when second recess portion 2241 is a hole penetratinglower washer 2235 and second protruding portion 2242 exceeds the wallthickness of lower washer 2235.

Embodiment 7

FIG. 14 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 7 of the present invention. FIG. 15 is an enlarged sectionalview showing a primary portion of the hermetic compressor of Embodiment7 of the present invention.

In FIGS. 14 and 15, refrigerant 2302 is charged into hermetic container2301. Further, refrigerating machine oil 2303 is stored in hermeticcontainer 2301. In this case, refrigerant 2302 is R600a which is ahydrocarbon refrigerant. Refrigerating machine oil 2303 is an oil, whichis compatible with refrigerant 2302, such as synthetic fluid, mineraloil or polyol ester oil.

Electric driving element 2311 includes: stator 2312 connected to anexternal electric power source (not shown); and rotor 2313 arranged,forming a predetermined gap between rotor 2313 and stator 2312.

Compression element 2321 includes: shaft 2322; cylinder block 2323;bearing 2324; piston 2325; connecting portion 2326; and thrust ballbearing 2331. Shaft 2322 includes: main shaft portion 2322 a, the outerdiameter of which is d; and eccentric shaft portion 2322 c connected tomain shaft portion 2322 a. Cylinder block 2323 composes compressionchamber 2323 a. Bearing 2324 supports shaft 2322, and is provided beingintegrated with cylinder block 2323 or being separated from cylinderblock 2323. Piston 2325 reciprocates in compression chamber 2323 a.Connecting portion 2326 connects piston 2325 with eccentric shaftportion 2322 c. Thrust ball bearing 2331 is arranged between the upperend face of bearing 2324 and rotor 2313 fixed to main shaft portion 2322a. Compression element 2321 composes a reciprocating type compressionmechanism.

Rotor 2313 is engaged with main shaft portion 2322 a of the shaft.Stator 2312 is arranged and fixed in an upper portion of cylinder block2323.

Thrust ball bearing 2331 includes: a plurality of balls 2332; holderportion 2333 for holding balls 2332; upper washer 2334 arranged aboveballs 2332; and lower washer 2335, arranged below the balls 2332.

Lower washer 2335 includes: rolling face 2336 with which balls 2332 comeinto contact; and cylindrical second bent portion 2341, the innerdiameter of which is C. Clearance (J−k)/2 in the thrust directionbetween inner diameter J of second bent portion 2341 and outer diameterk of bearing 2334 is smaller than clearance (C−d)/2 between innerdiameter C of lower washer 2335 and outer diameter d of main shaftportion 2322 a.

Since lower washer 2335 is made of carbon steel of not less than 70%,the hardness of lower washer 2335 is made to be about 95% of thehardness of balls 2332 of thrust ball bearing 2331. On rolling face 2336with which balls 2332 comes into contact, flatness is maintained to benot more than 30 microns. In order to ensure this flatness, rolling face2336 is formed by means of pushing. After that, rolling face 2136 issubjected to quenching so as to ensure the predetermined hardness andflatness.

Operation and action of the hermetic compressor composed as describedabove will be explained below.

When stator 2312 is energized by an external electric power source (notshown), rotor 2313 is rotated together with shaft 2322. Due to theforegoing, an eccentric motion is conducted by eccentric shaft portion2322 c. Therefore, eccentric shaft portion 2322 c reciprocates piston2325 through connecting portion 2326 in compression chamber 2323 a.Accordingly, a predetermined compressive motion to compress suction gasis conducted.

At this time, balls 2332 of thrust ball bearing 2231 support a verticalload generated by the dead weights of rotor 2313 and shaft 2322. Anupper surface of upper washer 2334 is closely contacted with a lower endsurface of rotor 2313 fixed to main shaft portion 2322 a throughviscosity of refrigerating machine oil 2303. Therefore, when shaft 2322is rotated, upper washer 2334 is rotated synchronously with shaft 2322.On the other hand, a lower surface of lower washer 2335 is also closelycontacted with an upper end portion of bearing 2324 through viscosity ofrefrigerating machine oil 2303. Therefore, lower washer 2335 is notrotated. Since slippage is generated between rotating balls 2332 andlower washer 2335, balls 2232 and holder portion 2333 are rotated beingdelayed without following a rotation of shaft 2322. In general, thecoefficient of rolling friction is 10 to 20 times as low as thecoefficient of sliding friction. Further, no metal contact is caused inthe rolling bearing. Therefore, it is possible to conduct a stablemotion by the rolling bearing.

Clearance (J−k)/2 in the thrust direction between inner diameter J ofsecond bent portion 2341 and outer diameter k of bearing 2334 is smallerthan clearance (C−d)/2 between inner diameter C of lower washer 2335 andouter diameter d of main shaft portion 2322 a. Therefore, before lowerwasher 2335 comes into contact with main shaft portion 2322 a, innerdiameter J of second bent portion 2341 and outer diameter k of bearing2324 come into contact with each other. That is, by second bent portion2341, lower washer 2335 is surely arranged at a position where the innerdiameter of lower washer 2335 is not contacted with rotating main shaftportion 2322 a.

As described above, when second bent portion 2341 is provided on theouter circumference of lower washer 2335, a regulation mechanism iscomposed.

Therefore, according to the present embodiment, the inner diameter oflower washer 2335 can be prevented from coming into contact with theouter diameter of main shaft portion 2322 a by this regulationmechanism. Accordingly, there is no possibility that main shaft portion2322 a is damaged by the lower washer 2335 and abrasion powder isgenerated. Therefore; it is possible to realize a highly reliablehermetic compressor.

Concerning thrust ball bearing 2331, only when shaft 2322 is insertedinto thrust ball bearing 2331 and second bent portion 2341 is idlyengaged with an upper end of bearing 2324 at the time of assembling, itis possible to incorporate thrust ball bearing 2331. That is, it isunnecessary to use a special assembling method such as press-fittinglower washer 2335. Accordingly, the property of assembling work can beenhanced.

Embodiment 8

FIG. 16 is a longitudinal sectional view of a hermetic compressor ofEmbodiment 8 of the present invention. FIG. 17 is an enlarged sectionalview showing a primary portion of the hermetic compressor of Embodiment8 of the present invention.

In FIGS. 16 and 17, refrigerant 2402 is charged into hermetic container2401. Further, refrigerating machine oil 2403 is stored in hermeticcontainer 2301. In this case, refrigerant 2402 is R600a which is ahydrocarbon refrigerant. Refrigerating machine oil 2403 is an oil, whichis compatible with refrigerant 2402, such as synthetic fluid, mineraloil or polyol ester oil.

Electric driving element 2411 includes: stator 2412 connected to anexternal electric power source (not shown); and rotor 2413 arranged,forming a predetermined gap between rotor 2413 and the inside of stator2412.

Compression element 2421 includes: shaft 2422; cylinder block 2423;bearing 2424; piston 2425; connecting portion 2426; and thrust ballbearing 2431. Shaft 2422 includes: main shaft portion 2422 a; andeccentric shaft portion 2422 c connected to main shaft portion 2422 a.Cylinder block 2423 composes compression chamber 2423 a. Bearing 2424supports shaft 2422, and is provided being integrated with cylinderblock 2423 or being separated from cylinder block 2423. Piston 2425reciprocates in compression chamber 2423 a. Connecting portion 2426connects piston 2425 with eccentric shaft portion 2422 c. Thrust ballbearing 2431 is arranged between the upper end face of bearing 2424 androtor 2413 fixed to main shaft portion 2422 a. Compression element 2421composes a reciprocating type compression mechanism.

Rotor 2413 is engaged with main shaft portion 2422 a of the shaft.Stator 2412 is arranged and fixed in an upper portion of cylinder block2423.

Thrust ball bearing 2431 includes: a plurality of balls 2432; holderportion 2433 for holding balls 2432; upper washer 2434 arranged aboveballs 2432; and lower washer 2435, arranged below the balls 2432. Inbearing 2424, at the height in which lower washer 2435 is arranged,second annular protruding portion 2441, which is surrounded inside thelower washer, is provided. Therefore, under the condition that the lowersurface of lower washer 2435 is closely contacted with an upper end faceof bearing 2424, an inner diameter of lower washer 2435 can not be movedinside from second annular protruding portion 2441.

Since lower washer 2435 is made of carbon steel of not less than 70%,the hardness of lower washer 2435 is made to be about 95% of thehardness of balls 2432 of thrust ball bearing 2431. On rolling face 2436with which balls 2432 comes into contact, flatness is maintained to benot more than 30 microns. Further, when rolling face 2436 is subjectedto quenching, predetermined hardness can be ensured.

Operation and action of the hermetic compressor composed as describedabove will be explained below.

When stator 2412 is energized by an external electric power source (notshown), rotor 2413 is rotated together with shaft 2422. Due to theforegoing, an eccentric motion is conducted by eccentric shaft portion2422 c. Therefore, eccentric shaft portion 2422 c reciprocates piston2425 through connecting portion 2426 in compression chamber 2423 a.Accordingly, a predetermined compressive motion to compress suction gasis conducted.

At this time, balls 2432 of thrust ball bearing 2431 support a verticalload generated by the dead weights of rotor 2413 and shaft 2422. Anupper surface of upper washer 2434 is closely contacted with a lower endsurface of rotor 2413 fixed to main shaft portion 2422 a throughviscosity of refrigerating machine oil 2403. Therefore, when shaft 2422is rotated, upper washer 2434 is rotated synchronously with shaft 2422.On the other hand, a lower surface of lower washer 2435 is also closelycontacted with an upper end portion of bearing 2424 through viscosity ofrefrigerating machine oil 2403. Therefore, lower washer 2435 is notrotated. Since slippage is generated between rotating balls 2432 andlower washer 2435, balls 2432 and holder portion 2433 are rotated beingdelayed without following a rotation of shaft 2422. In general, thecoefficient of rolling friction is 10 to 20 times as low as thecoefficient of sliding friction. Further, no metal contact is caused inthe rolling bearing. Therefore, it is possible to conduct a stablemotion by the rolling bearing.

Since second annular protruding portion 2441 exists between an innerdiameter of lower washer 2435 and an outer diameter of main shaftportion 2422 a, the inner diameter of lower washer 2435 comes intocontact with second annular protruding portion 2441 before it comes intocontact with the outer diameter of main shaft portion 2422 a. That is,by second annular protruding portion 2441, the inner diameter of lowerwasher 2435 is surely arranged at a position where the inner diameter oflower washer 2435 does not come into contact with the outer diameter ofrotating main shaft portion 2422 a.

When the annular protruding portion is provided inside the upper endface of the bearing, a regulation mechanism is composed.

Therefore, according to the present embodiment, the inner diameter oflower washer 2435 can be prevented from coming into contact with theouter diameter of main shaft portion 2422 a by this regulationmechanism. Accordingly, there is no possibility that main shaft portion2422 a is damaged and abrasion powder is generated. Therefore, it ispossible to realize a highly reliable hermetic compressor.

Second annular protruding portion 2441 can be formed, for example,simultaneously when bearing 2424 is molded by means of die-cast molding.Therefore, it is unnecessary to add a manufacturing step. Accordingly,it is possible to enhance the productivity of producing a hermeticcompressor.

Since thrust ball bearing 2431 can be incorporated into the device onlywhen shaft 2422 is inserted into the thrust ball bearing and when lowerwasher 2435 is arranged so that the inner diameter of lower washer 2435can be laid along the outer diameter of second annular protrudingportion 2441, it is unnecessary to use a special assembling method suchas a method of press-fitting lower washer 2435. Accordingly, the workingproperty can be enhanced at the time of assembling.

In this connection, in the present embodiment, second annular protrudingportion 2441 is arranged at a height in which lower washer 2435 isarranged. However, as long as second annular protruding portion 2441 isout of the rotary locus of balls 2432 controlled by holder portion 2433and as long as second annular protruding portion 2441 is arranged in arange in which rotation of balls 2432 is not obstructed, even whensecond annular protruding portion 2441 exceeds the wall thickness oflower washer 2435, the same operational effect can be provided.

INDUSTRIAL APPLICABILITY

A hermetic compressor of the present invention is highly efficient andreliable. Therefore, the hermetic compressor of the present inventioncan be applied to a refrigerating compressor incorporated into an airconditioner, a refrigerator and so forth.

1. A hermetic compressor comprising: an electrically driving elementhaving a stator and a rotor, the electrically driving element beingaccommodated in a hermetic container; and a compression element drivenby the electrically driving element, the compression element beingaccommodated in the hermetic container, the compression elementcomprising: a shaft; a cylinder block forming a compression chamber; abearing for supporting the shaft, arranged in the cylinder block; apiston reciprocated in the compression chamber; a connecting portion forconnecting the piston with an eccentric shaft portion; and a thrust ballbearing, the thrust ball bearing comprising: a plurality of balls; aholder portion for holding the balls; an upper washer arranged above theballs; and a lower washer arranged below the balls, the hermeticcompressor further comprising a regulation mechanism for regulating thelower washer so that a movable distance in the thrust direction of thelower washer can be shorter than clearance formed between an innerdiameter of the lower washer and an outer diameter of the main shaftportion.
 2. The hermetic compressor of claim 1, wherein the shaftcomprises a main shaft portion and an eccentric shaft portion formedthrough a flange portion; and wherein the thrust ball bearing isarranged between the flange portion and an upper end face of thebearing.
 3. The hermetic compressor of claim 2, wherein the regulationmechanism comprises a first cylindrical wall, which is arranged in thecylinder block or the bearing, surrounding the outside of the lowerwasher; and wherein clearance between an outer diameter of the lowerwasher and an inner diameter of the first cylindrical wall is smallerthan clearance between an inner diameter of the lower washer and anouter diameter of the main shaft portion.
 4. The hermetic compressor ofclaim 2, wherein the regulation mechanism comprises a first recessportion and a first protruding portion which are idly engaged with eachother and respectively arranged on the lower washer and the upper endface of the bearing; and wherein clearance in the thrust directionbetween the first recess portion and the first protruding portion issmaller than clearance between an inner diameter of the lower washer andan outer diameter of the main shaft portion.
 5. The hermetic compressorof claim 2, wherein the regulation mechanism comprises a first bentportion on an outer circumference of the lower washer; and whereinclearance in the thrust direction between an inner circumferential faceof the first bent portion and an outer diameter of the bearing issmaller than clearance between an inner diameter of the lower washer andan outer diameter of the main shaft portion.
 6. The hermetic compressorof claim 2, wherein the regulation mechanism comprises a first annularprotruding portion arranged inside an upper end face of the bearing; andwherein the first annular protruding portion and an inner circumferenceof the lower washer are idly engaged with each other.
 7. The hermeticcompressor of claim 1, wherein the shaft comprises a main shaft portionto which the eccentric shaft portion and the rotor are fixed; andwherein the thrust ball bearing is arranged between an upper end face ofthe bearing and the rotor fixed to the main shaft portion.
 8. Thehermetic compressor of claim 7, wherein a second cylindrical wall forsurrounding the outside of the lower washer is provided in an upperportion of the bearing; and wherein the regulation mechanism is composedin such a manner that clearance between an outer diameter of the lowerwasher and an inner diameter of the second cylindrical wall is smallerthan clearance between an inner diameter of the lower washer and anouter diameter of the main shaft portion.
 9. The hermetic compressor ofclaim 7, wherein the regulation mechanism comprises a second recessportion and a second protruding portion which are idly engaged with eachother and respectively arranged on the lower washer and the upper endface of the bearing; and wherein clearance in the thrust directionbetween the second recess portion and the second protruding portion issmaller than clearance between an inner diameter of the lower washer andan outer diameter of the main shaft portion.
 10. The hermetic compressorof claim 7, wherein the regulation mechanism comprises a second bentportion on an outer circumference of the lower washer; and whereinclearance in the thrust direction between an inner circumferential faceof the second bent portion and an outer diameter of the bearing issmaller than clearance between an inner diameter of the lower washer andan outer diameter of the main shaft portion.
 11. The hermetic compressorof claim 7, wherein the regulation mechanism comprises a second annularprotruding portion arranged inside an upper end face of the bearing; andwherein the second annular protruding portion and an inner circumferenceof the lower washer are idly engaged with each other.